Cable television (CATV) is a system of providing television, internet data, and/or other services to consumers via radio frequency signals transmitted to one or more customer premises through, but not limited to, optical fibers or coaxial cables as opposed to the over-the-air method used in traditional television broadcasting via radio waves.
A Data Over Cable Service Interface Specification (DOCSIS) communications system includes two primary components: a Set-top Device, such as a cable modem or home gateway to provide some examples, located at the customer premises, and a Cable Modem Termination System (CMTS) located at a headend. DOCSIS is a standard for cable modem interfaces that defines communications and operation support interface requirements for a transfer of data over cable systems. The DOCSIS specification permits the addition of high-speed data transfer to an existing cable TV (CATV) system. For example, many cable television networks employ the DOCSIS specification to provide Internet access over networks such as Hybrid Fiber Coaxial (HFC) networks.
The one or more customer premises, such as customer televisions to provide an example, and associated peripherals are termed Customer Premise Equipment (CPE). The CPE is connected to the Set-top Device, which is in turn connected through the network to the CMTS. The CMTS routes traffic between the network and the Internet. Using the CMTS, a cable operator can control a configuration of the Set-top Device. The configuration of the Set-top Device may be changed to adjust for varying line conditions and/or customer service requirements.
According to the DOCSIS specification, the Set-top Device must report the actual received desired channel power at the Set-top Device from the downstream transmit power of the CMTS within 3 decibels (dB) when operating at a nominal line voltage and/or at a normal room temperature. The DOCSIS specification also provides that across an input power range from −15 dBmV to +15 dBmV, where dBmV represents a voltage relative to one millivolt, the Set-top Device must report a power change in the same direction that is not less than 0.5 dB and not more than 1.5 dB for any 1 dB change in the actual received channel power.
Conventional methods to report the desired channel input power at the Set-top Device from the downstream transmit power of the CMTS require the use of extensive look-up tables stored in a memory storage device, such as a Random Access Memory (RAM), a Dynamic RAM (DRAM), a Synchronous DRAM (SDRAM), a Double Data Rate SDRAM (DDR SDRAM), a hard disk drive, and/or a flash drive such as a Universal Serial Bus (USB) flash drive to provide some examples. These look-up tables may require vast spaces of memory for storage and need to be reconfigured as the components of the Set-top Device change or deteriorate over time. In addition, the look-up tables may need to be modified in a calibration operation during manufacturing, thereby adding to cost.
Similar power reporting requirements, such as those described above, are currently being considered for other broadcast systems, such as satellite television to provide an example.
Thus, what is needed is a system and a method to report the desired channel input power from the downstream transmit power of the broadcast system to overcome the shortcomings stated above.
The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.